# US 5,700,489 A · Bubble stabilizer and sizing cage with wear strips > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,700,489 A - Document ID: US5700489A - Status: Granted - Kind: A - Application number: 08/653,791 - Filed: 1996-05-28 - Granted: 1997-12-23 - Earliest claimed: 1996-05-28 - Assignees: Pearl Technologies, Inc. - Inventors: Earl T. Pottorff - Web page: https://patentgrep.com/patent/US5700489A ## CPC - B29C 48/908: {characterised by calibrator surface, e.g. structure or holes for lubrication, cooling or venting} - B29C 48/09: Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels - B29C 48/10: flexible, e.g. blown foils - B29C 48/12: Articles with an irregular circumference when viewed in cross-section, e.g. window profiles - B29C 48/901: {of hollow bodies} - B29C 48/903: {externally} - B29C 48/907: {using adjustable calibrators, e.g. the dimensions of the calibrator being changeable} - B29C 48/885: External treatment, e.g. by using air rings for cooling tubular films - B29C 48/912: {of tubular films} - B29C 48/9135: {of flat articles, e.g. using specially adapted supporting means} - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) ## Abstract An external stabilizer employed in a plastic film blowing apparatus incorporates one or more extruded members that carry a low-friction plastic wear cover. A tubular die, fed with a supply of molten thermoplastic polymer, extrudes a tube of the molten polymer and injects air into said extruded tube to inflate the tube into a bubble. The wall of the tube expands into a film of a desired thickness; and the tube is drawn vertically upward and collapsed and flattened. The external stabilizer is positioned on a frame surrounding the extruded tube above the die to keep the tube aligned on a predetermined path as the tube is drawn upwards. The stabilizer includes at least one extrusion of a light-weight material having a profile that is rounded on a side that faces the extruded tube so that said extrusion has a rounded front surface. The associated wear cover is made of a wear resistant plastic material and is disposed on said rounded front surface of said extrusion. In one possible embodiment, the stabilizer comprises a plurality of banks of curved arms. In another embodiment, the stabilizer is formed as an extruded helix. The extrusion can be aluminum and with a mushroom-shaped cross section. Preferably, the extrusion has a hollow core and is fitted with piping for fluid cooling. ## Claims ### Claim 1 In an external stabilizer arrangement of the type employed in a plastic film blowing apparatus in which a tubular die means, fed with a supply of molten thermoplastic polymer, extrudes a tube of the molten polymer and which injects air into said extruded tube to inflate the tube and expand the wall of the tube into a film of a desired thickness; and wherein means positioned above said die means draw the tube vertically upward along a vertical axis and collapse and flatten the film; the external stabilizer arrangement being positioned on frame means surrounding the extruded tube above said die means to keep the tube aligned on a predetermined path as the tube is drawn upwards; comprising the improvement wherein said stabilizer arrangement includes at least one extrusion of a light-weight material curved in a circumferential direction about said vertical axis, and having a profile that is rounded on a side that faces the extruded tube so that said extrusion has a rounded front surface; and a wear resistant material disposed non-rotatably on said rounded front surface of said extrusion. ### Claim 2 (depends on 1) The external stabilizer arrangement of claim 1, wherein said light-weight material is a non-ferrous metal. ### Claim 3 (depends on 1) The external stabilizer arrangement of claim 1, wherein said light-weight material includes aluminum. ### Claim 4 (depends on 1) The external stabilizer arrangement of claim 1, wherein said wear resistant material comprises a wear cover removably fitted onto the front surface of said extrusion of light-weight material, and being formed of a plastic synthetic resin that is impregnated with a lubricating agent. ### Claim 5 (depends on 4) The external stabilizer arrangement of claim 4, wherein said wear cover has a profile that is generally C-shaped. ### Claim 6 (depends on 4) The external stabilizer arrangement of claim 4, wherein said extrusion of light-weight material has upper and lower recesses behind said rounded front surface and said wear cover includes upper and lower inwardly directed flanges that fit into said recesses to retain the wear cover on said extrusion. ### Claim 7 (depends on 1) The external stabilizer arrangement of claim 1, wherein said at least one extrusion is in the form of a plurality of curved arms. ### Claim 8 (depends on 1) The external stabilizer arrangement of claim 1, wherein said at least one extrusion is in the form of a helical coil of a plurality of turns. ### Claim 9 (depends on 1) The external stabilizer arrangement of claim 1, wherein said extrusion of light-weight material has an interior opening that extends the length thereof; and further including piping means for permitting a fluid coolant to flow through said interior opening. ### Claim 10 An external stabilizer arrangement for a plastic film blowing apparatus in which tubular die means, fed with a supply of molten thermoplastic polymer, extrudes a tube of the molten polymer and which injects air into said extruded tube to inflate the tube and expand the wall of the tube into a film of a desired thickness; and wherein means positioned above said die means draw the tube vertically upward along a vertical axis and collapse and flatten the film; the external stabilizer arrangement comprising frame means surrounding the extruded tube above said die means; and a plurality of arcuate guide arms supported on said frame means and disposed circumferentially about said extruded tube; each said arcuate guide arm including an extrusion of a light-weight metal that curves in an are in a direction that is generally circumferential about said axis, and having a profile that is rounded on a side that faces the extruded tube such that said extrusion has a rounded front surface; and a wear resistant material disposed non-rotatably on said rounded front surface of said extrusion. ### Claim 11 (depends on 10) The external stabilizer of claim 10 wherein said extrusion of light-weight material has a generally mushroom-shaped cross section. ### Claim 12 (depends on 10) The external stabilizer of claim 10 wherein said said extrusion has an interior opening that extends for the length of said arm, and piping means for creating a flow of a fluid coolant through said enterior opening. ### Claim 13 (depends on 10) The external stabilizer of claim 10 wherein said wear resistant material includes a wear cover fitted onto the front surface of said extrusion, and being formed of a plastic synthetic resin that is impregnated with a lubricating agent. ### Claim 14 (depends on 4) The external stabilizer of claim 4, wherein said wear cover has a profile that is half round, with inwardly projecting flanges at upper and lower edges of the wear cover.